/usr/lib/python2.7/dist-packages/iapws/iapws08.py is in python-iapws 1.1.3-1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 | #!/usr/bin/python
# -*- coding: utf-8 -*-
###############################################################################
# IAPWS for seawater
###############################################################################
from __future__ import division
from math import log
from .iapws95 import IAPWS95
# Constants
Rm = 8.314472
Sn = 0.03516504
S_ = Sn*40/35
Ms = 31.4038218
T_ = 40
P_ = 100
Po = 0.101325
To = 273.15
class SeaWater(object):
"""
Class to model seawater with standard IAPWS-08
Incoming properties:
T - Temperature, K
P - Pressure, MPa
S - Salinity, kg/kg
Calculated properties:
T: Temperature, K
P: Pressure, MPa
rho: Density, kg/m³
v: Specific volume, m³/kg
h: Specific enthalpy, kJ/kg
s: Specific entropy, kJ/kg·K
u: Specific internal energy, kJ/kg
g: Specific Gibbs free energy, kJ/kg
a: Specific Helmholtz free energy, kJ/kg
cp: Specific isobaric heat capacity, kJ/kg·K
gt: Derivative Gibbs energy with temperature, kJ/kg·K
gp: Derivative Gibbs energy with pressure, m³/kg
gtt: Derivative Gibbs energy with temperature square, kJ/kg·K²
gtp: Derivative Gibbs energy with pressure and temperature, m³/kg·K
gpp: Derivative Gibbs energy with temperature square, m³/kg·MPa
gs: Derivative Gibbs energy with salinity, kJ/kg
gsp: Derivative Gibbs energy with salinity and pressure, m³/kg
alfa: Thermal expansion coefficient, 1/K
betas: Isentropic temperature-pressure coefficient, K/MPa
kt: Isothermal compressibility, 1/MPa
ks: Isentropic compressibility, 1/MPa
w: Sound Speed, m/s
mu: Relative chemical potential, kJ/kg
muw: Chemical potential of H2O, kJ/kg
mus: Chemical potential of sea salt, kJ/kg
osm: Osmotic coefficient, [-]
haline: Haline contraction coefficient, kg/kg
"""
kwargs = {"T": 0.0,
"P": 0.0,
"S": None}
status = 0
msg = "Undefined"
def __init__(self, **kwargs):
"""Constructor, initinialice kwargs"""
self.kwargs = SeaWater.kwargs.copy()
self.__call__(**kwargs)
def __call__(self, **kwargs):
"""Make instance callable to can add input parameter one to one"""
self.kwargs.update(kwargs)
if self.kwargs["T"] and self.kwargs["P"] and \
self.kwargs["S"] is not None:
self.status = 1
self.calculo()
self.msg = ""
def calculo(self):
"""Calculate procedure"""
T = self.kwargs["T"]
P = self.kwargs["P"]
S = self.kwargs["S"]
m = S/(1-S)/Ms
pw = self._water(T, P)
ps = self._saline(T, P, S)
prop = {}
for key in pw:
prop[key] = pw[key]+ps[key]
self.__setattr__(key, prop[key])
self.T = T
self.P = P
self.rho = 1./prop["gp"]
self.v = prop["gp"]
self.s = -prop["gt"]
self.cp = -T*prop["gtt"]
self.h = prop["g"]-T*prop["gt"]
self.u = prop["g"]-T*prop["gt"]-P*1000*prop["gp"]
self.a = prop["g"]-P*1000*prop["gp"]
self.alfa = prop["gtp"]/prop["gp"]
self.betas = -prop["gtp"]/prop["gtt"]
self.kt = -prop["gpp"]/prop["gp"]
self.ks = (prop["gtp"]**2-prop["gt"]*prop["gpp"])/prop["gp"]/prop["gtt"]
self.w = prop["gp"]*(prop["gtt"]*1000/(prop["gtp"]**2 -
prop["gtt"]*1000*prop["gpp"]*1e-6))**0.5
self.mu = prop["gs"]
self.muw = prop["g"]-S*prop["gs"]
self.mus = prop["g"]+(1-S)*prop["gs"]
self.osm = -(ps["g"]-S*prop["gs"])/m/Rm/T
self.haline = -prop["gsp"]/prop["gp"]
@classmethod
def _water(cls, T, P):
"""Get properties of pure water, Table4 pag 8"""
water = IAPWS95(P=P, T=T)
prop = {}
prop["g"] = water.h-T*water.s
prop["gt"] = -water.s
prop["gp"] = 1./water.rho
prop["gtt"] = -water.cp/T
prop["gtp"] = water.betas*water.cp/T
prop["gpp"] = -1e6/(water.rho*water.w)**2-water.betas**2*1e3*water.cp/T
prop["gs"] = 0
prop["gsp"] = 0
return prop
@classmethod
def _saline(cls, T, P, S):
"""Eq 4"""
S_ = 0.03516504*40/35
X = (S/S_)**0.5
tau = (T-273.15)/40
pi = (P-0.101325)/100
I = [1, 2, 3, 4, 5, 6, 7, 1, 2, 3, 4, 5, 6, 2, 3, 4, 2, 3, 4, 2, 3, 4,
2, 4, 2, 2, 3, 4, 5, 2, 3, 4, 2, 3, 2, 3, 2, 3, 2, 3, 4, 2, 3, 2,
3, 2, 2, 2, 3, 4, 2, 3, 2, 3, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2]
J = [0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4,
5, 5, 6, 0, 0, 0, 0, 1, 1, 1, 2, 2, 3, 3, 4, 4, 0, 0, 0, 1, 1, 2,
2, 3, 4, 0, 0, 0, 1, 1, 2, 2, 3, 4, 0, 0, 1, 2, 3, 0, 1, 2]
K = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2,
2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 5, 5, 5]
G = [0.581281456626732e4, 0.141627648484197e4, -0.243214662381794e4,
0.202580115603697e4, -0.109166841042967e4, 0.374601237877840e3,
-0.485891069025409e2, 0.851226734946706e3, 0.168072408311545e3,
-0.493407510141682e3, 0.543835333000098e3, -0.196028306689776e3,
0.367571622995805e2, 0.880031352997204e3, -0.430664675978042e2,
-0.685572509204491e2, -0.225267649263401e3, -0.100227370861875e2,
0.493667694856254e2, 0.914260447751259e2, 0.875600661808945,
-0.171397577419788e2, -0.216603240875311e2, 0.249697009569508e1,
0.213016970847183e1, -0.331049154044839e4, 0.199459603073901e3,
-0.547919133532887e2, 0.360284195611086e2, 0.729116529735046e3,
-0.175292041186547e3, -0.226683558512829e2, -0.860764303783977e3,
0.383058066002476e3, 0.694244814133268e3, -0.460319931801257e3,
-0.297728741987187e3, 0.234565187611355e3, 0.384794152978599e3,
-0.522940909281335e2, -0.408193978912261e1, -0.343956902961561e3,
0.831923927801819e2, 0.337409530269367e3, -0.541917262517112e2,
-0.204889641964903e3, 0.747261411387560e2, -0.965324320107458e2,
0.680444942726459e2, -0.301755111971161e2, 0.124687671116248e3,
-0.294830643494290e2, -0.178314556207638e3, 0.256398487389914e2,
0.113561697840594e3, -0.364872919001588e2, 0.158408172766824e2,
-0.341251932441282e1, -0.316569643860730e2, 0.442040358308000e2,
-0.111282734326413e2, -0.262480156590992e1, 0.704658803315449e1,
-0.792001547211682e1]
g, gt, gp, gtt, gtp, gpp, gs, gsp = 0, 0, 0, 0, 0, 0, 0, 0
for i, j, k, gi in zip(I, J, K, G):
if i == 1:
g += gi*X**2*log(X)*tau**j*pi**k
gs += gi*(2*log(X)+1)*tau**j*pi**k
else:
g += gi*X**i*tau**j*pi**k
gs += i*gi*X**(i-2)*tau**j*pi**k
if j >= 1:
if i == 1:
gt += gi*X**2*log(X)*j*tau**(j-1)*pi**k
else:
gt += gi*X**i*j*tau**(j-1)*pi**k
if k >= 1:
gp += k*gi*X**i*tau**j*pi**(k-1)
gsp += i*k*gi*X**(i-2)*tau**j*pi**(k-1)
if j >= 2:
gtt += j*(j-1)*gi*X**i*tau**(j-2)*pi**k
if j >= 1 and k >= 1:
gtp += j*k*gi*X**i*tau**(j-1)*pi**(k-1)
if k >= 2:
gpp += k*(k-1)*gi*X**i*tau**j*pi**(k-2)
prop = {}
prop["g"] = g*1e-3
prop["gt"] = gt/40*1e-3
prop["gp"] = gp/100*1e-6
prop["gtt"] = gtt/40**2*1e-3
prop["gtp"] = gtp/40/100*1e-6
prop["gpp"] = gpp/100**2*1e-6
prop["gs"] = gs/S_/2*1e-3
prop["gsp"] = gsp/S_/2/100*1e-6
return prop
if __name__ == "__main__":
import doctest
doctest.testmod()
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